With development of communications technologies, a radio network continuously evolves. Currently, an all-Internet Protocol (IP) architecture is implemented in a Long Term Evolution (LTE) network. Because the LTE network supports only a packet switched (PS) domain service, a voice service is borne on an IP transport network, and therefore is referred to as a Voice over Internet Protocol (VOIP) service. The VOIP service is also referred to as a VoLTE service in an LTE system.
With large-scale use of the LTE network, the VOIP service is increasingly popular. How to improve voice communication quality is gaining more attention.